In a system which is known from European Patent Publication 214,453, which corresponds to U.S. Pat. No. 4,868,796 of Sep. 19, 1989, and serves to determine the position of an object relative to handling means, at least three spaced apart ultrasonic sensors are provided, which are directed at an angle to a common reference plane and detect elongate line-like features, by which the sound waves of the sensors are reflected parallel to the direction of incidence. Handling means which are controlled by ultrasonic sensors have only a relatively limited field of application because the detection of an object will not be ensured, on principle, unless the distance from the ultrasonic sensors to the ultrasonic reflectors is not in excess of 500 to 700 mm.
It has previously been believed that video optical sensors are less suitable for a determination of the position of objects and for generation of signals for controlling handling means because such sensors are subject to strong restrictions due to the current illuminating conditions, color contrasts and the features to be detected. For this reason it is an object of the invention to provide a system of the kind stated first hereinbefore which is robust and immune to interference and permits the reliable detection of objects and the determination of their spatial position and which will generate signals that correspond to the measured position of an object and can be processed by an electronic computer.